<?php
    if ($_POST) {
        $link = mysql_connect("localhost", "root", "Gilad2007");
        if (!$link) {
            die("Couldn't access the server: " . mysql_error());
            exit;
        }

        $db_selected = mysql_select_db("MySite", $link);
        if (!$db_selected) {
            die("Can't access the selected database: " . mysql_error());
            exit;
        }

        $provided_username = $_POST['username'];
        $provided_password = $_POST['password'];

        if (!$provided_username or !$provided_password) {
            //Add error message: "Please enter both username and password."
        }

        $sql = sprintf("select password from clients where username='%s'",
                mysql_real_escape_string($provided_username));

        $result = mysql_query($sql);

        $access = FALSE;
        while ($row = mysql_fetch_assoc($result)) {
            if ($row['password'] == $provided_password) {
                $access = TRUE;
                break;
            }
        }

        //Add session start!
        if ($access == TRUE) {
            print "Login Succeded!";
        }

        else {
            print "Login Failed!";
        }
    }

?>